Separate providers' networks, commonly referred to as “clouds” are interconnected via Network Network Interfaces (NNIs) to create networks spanning vast geographic areas, so that providers may offer services that cannot be offered by any single provider. In order to achieve the fastest reaction to node or link failures, some form of protection switching is common. Buffer networks are networks whose physical topology, configuration enable it to guarantee, even in the face of some number of node or link failures, to proved connectivity among all of its NNIs.